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Take a Bite Out of Hypoglycemia
Is it really possible to have too much of a good thing? Take my own “good things” list as an example. I really enjoy eating popcorn at the movies, lying on the beach, and taking my kids to ballgames. Good things, yes, but only in moderation. If left unchecked, I might become broke, obese, and badly sunburned.
For millions of people with diabetes, insulin and oral medicines that stimulate the pancreas to release more of its own insulin are good things. Without them, blood glucose levels would become wildly out of control. But when taken in too great a quantity, they can produce the opposite extreme: low blood glucose, or hypoglycemia.
Physicians usually advise people to avoid blood glucose levels below 60 or 70 mg/dl (it varies depending on which book you read and where your health-care provider studied). At this low level, many of the body’s key organs, especially the brain and nervous system, become deprived of the fuel they need to function properly.
Greatest limiting factor
First and foremost is the risk to one’s personal safety. The brain is one of the first organs to be affected by low blood glucose. When the brain receives inadequate fuel, confusion and poor decision-making often result. This can easily lead to life-threatening accidents, loss of consciousness, coma, and possibly even death if left untreated for too long.
Personal performance is another area affected by hypoglycemia. The ability to perform in sports, school, work, and social situations is affected negatively by low blood glucose. In many ways, having low blood glucose is similar to being drunk: It affects our movements, our thoughts, and virtually everything we say and do.
The brain’s ability to detect low blood glucose is an important protective mechanism. However, this mechanism is blunted by repeated bouts of hypoglycemia. With each low, the brain becomes less and less sensitive to the lows — perhaps not recognizing them at all. Without the brain’s reaction to the low, a person with diabetes may remain completely oblivious to the problem. This condition, known as hypoglycemia unawareness, puts a person at risk for severe hypoglycemia (leading to loss of consciousness, etc.) because of the lack of an “early warning” system.
In extreme cases, hypoglycemia can even cause permanent brain damage. With every episode of hypoglycemia, some brain cells die. Considering that you start with billions of brain cells, losing a few here and there is not likely to make any significant difference. However, repeated bouts of severe or prolonged hypoglycemia have the potential to create noticeable cognitive deficits.
In many instances, low blood glucose also causes anxiety or embarrassment. Some people with diabetes worry about the impression left on others by a hypoglycemic episode. Does it make me look sick? Different? Like I’m not “in control”? The fear of experiencing hypoglycemia in a social setting leads many people toward the opposite extreme: maintaining high blood glucose levels around the clock.
Because of the need to eat extra food to treat low blood glucose, weight gain can also become an issue. Hypoglycemia can produce a werewolf-size appetite, resulting in the consumption of excessive calories for several hours. If low blood glucose occurs frequently or is consistently overtreated, weight gain will likely result.
Additionally, did you know that low blood glucose can produce significant highs? A rebound, as this is called, is the body’s natural hormonal response to the low. Once hypoglycemia is detected by the brain, adrenaline starts to flow into the bloodstream along with other blood-glucose-raising counterregulatory hormones such as cortisol and glucagon. Collectively, these hormones stimulate the liver to release stored glucose, which can cause blood glucose to stay high for many hours following a bout of hypoglycemia.
What should I aim for?
(Combination medicines that contain sulfonylureas, such as Glucovance, Metaglip, Avandaryl, and Duetact, and combination medicines that contain meglitinides, such as Prandimet, can also cause hypoglycemia.)
So what is realistic? For starters, accept that an occasional low can occur. It is reasonable to experience mild low blood glucose a couple of times each week — lows that you can detect and treat without outside assistance. It is never acceptable to experience a severe episode of hypoglycemia (a low that causes a loss of consciousness, seizure, or unresponsiveness). Following any low that requires emergency medical assistance, additional self-management education and greater attention to control is always in order. A change in therapy may also be necessary.
If you check your blood glucose at each mealtime and bedtime, try to have no more than 10% of your readings below 70 mg/dl (or 80 mg/dl for very young children) at each test time. For example, let’s say you collect your readings for an entire month (31 days) and find the following:
The conclusion would be that there are too many lows at bedtime. A reduction in the dinnertime insulin (or oral medicine) may be in order. The number of lows at breakfast, lunch, and dinner appears to be acceptable.
For people with Type 2 diabetes, multiple episodes of hypoglycemia are a sign that insulin and/or oral medicines should be reduced. This, in turn, will help with any weight-loss efforts. In addition, people with existing heart disease should try to avoid hypoglycemia entirely. If you have heart disease, let your doctor know if you experience any lows.
1. Match your insulin or medicine program to your needs.
Mealtime insulin should match your typical blood glucose rise caused by dietary carbohydrate. Most starchy and sugary foods cause a rapid blood glucose rise, with a peak occurring about an hour after eating. Rapid-acting insulin analogs do a nice job of covering the rapid blood glucose rise and then dissipating before they can cause hypoglycemia later on. Regular insulin tends to peak too late and last too long, increasing the risk of hypoglycemia several hours after eating.
For those taking pancreas-stimulating oral medicines, be aware that some — glimepiride, glipizide, glyburide, chlorpropamide, tolazamide, and tolbutamide — work constantly (whether you are eating or not), while others — nateglinide and repaglinide — work for a short time (just after eating). Obviously, nateglinide and repaglinide are less likely to cause between-meal lows.
2. Set an appropriate target.
3. Take a look at your schedule.
4. Use caution when “covering” high blood glucose.
Also, be certain to account for “unused” insulin (the amount that is still active from the previous dose). With rapid-acting insulin analogs, it usually takes about 3–5 hours for the insulin’s activity to fade completely. Regular insulin takes about 5–6 hours. A blood glucose reading taken 2 hours after a meal can be misleading since the insulin still packs a good deal of punch and the blood glucose should continue to drop. (See “Accounting for Unused Insulin” for guidelines on how to take still-active insulin into account.)
For those who take daytime intermediate-acting insulin, it can be difficult and dangerous to correct for high blood glucose until the intermediate-acting insulin has worn off. NPH insulin does not always get absorbed or act in a predictable manner. In general, to avoid hypoglycemia, it is best to wait at least 10 hours after taking NPH before correcting for high readings.
5. Adjust doses based on carbohydrate intake.
Carbohydrate also acts differently throughout the day. Most people need different doses of insulin or oral medicine to cover their carbohydrate at different meals. This is caused by varying levels of stress, insulin sensitivity, and physical activity throughout the day.
And if you’re going to go to the trouble of matching your doses to your carbohydrate intake, be sure that your carbohydrate counts are reasonably accurate. Look up the exact carbohydrate count for foods you are unfamiliar with. (An excellent resource for looking up carbohydrate counts is The Doctor’s Pocket Calorie, Fat and Carb Counter, which is available through your local bookstore or online.) Measure your portions. And don’t forget to deduct all of the fiber grams and half of the sugar alcohols from the total carbohydrate count; fiber is a carbohydrate that is not digested, and sugar alcohols only raise the blood glucose about half as much as an equivalent amount of ordinary carbohydrate.
6. Extend or delay your mealtime insulin when necessary.
It is advisable to extend or delay your insulin when consuming food for a prolonged time, such as at a holiday meal or when eating a bucket of popcorn at the movies. Very large food portions also take a long time to digest. Think of your stomach as an hourglass and the food as sand trickling through. A very large portion of food, especially with a high fat content, might take several hours to pour through the stomach and into the intestines where it can be absorbed into the bloodstream, while a small portion will pour through relatively quickly.
In addition, a person who has gastroparesis (a nerve condition that causes the stomach to empty more slowly than usual) would also benefit from extending or delaying his mealtime insulin.
Extending or delaying insulin delivery can be accomplished in a number of ways. People who use mealtime rapid-acting insulin can take it 15–30 minutes after eating instead of before or during the meal. The dose could also be split into two injections — taking 50% with the meal and taking the other 50% an hour or two later. Alternatively, Regular insulin can be used instead of rapid-acting insulin when a slow-digesting meal is consumed.
For those who use an insulin pump, there are several options for prolonging or delaying the action of the mealtime bolus. Almost all pumps allow the bolus to be delivered over an hour or more (using the Square Wave or Extended boluses feature). Some allow a portion of the bolus, such as 33%, to be delivered immediately while delivering the remainder over the next couple of hours (Dual Wave or Combination boluses).
7. Adjust for physical activity.
Work with your health-care provider to develop a plan to reduce your insulin or oral medicine when physical activity is anticipated. There is no way to tell exactly how much the activity will lower your blood glucose, so you might start out by reducing your dose by 33% when activity is planned within 90 minutes of the meal. For more intense activity, a 50% (or greater) reduction can be made; for less intense activity, a 20% or 25% reduction may be sufficient.
For activity that will take place before or between meals, it makes more sense to check your blood glucose and have a snack before you exercise. Again, the size of the snack depends on many variables, including your body size, the nature of the activity, and the timing and amount of your last dose of insulin or oral medicine. As a general rule, people who weigh 100 pounds will need approximately 15–25 grams of carbohydrate per hour of activity to keep their blood glucose steady. Those who weigh 150 pounds will need 20–30 grams; 200 pounds: 25–35 grams; 250 pounds: 30–40 grams, and so on.
Don’t forget that physical activity that is very intense and prolonged can produce a blood glucose drop several hours later. This is called “delayed-onset hypoglycemia.” Many people find that their blood glucose drops during the night following heavy daytime exercise, or in the morning following heavy exercise the night before.
Check your blood glucose more often than usual for up to 24 hours following heavy exercise. If you detect a pattern of delayed-onset hypoglycemia, you can prevent it by consuming extra carbohydrate or by lowering your insulin or oral medicine at the appropriate time. For example, to prevent the late-morning drops following nighttime exercise, try lowering your insulin dose at breakfast by 33%.
8. Be aware of alcohol’s effects.
After drinking alcohol, it is recommended that you reduce your insulin or diabetes medicine dose or consume extra carbohydrate. People who use insulin pumps can lower their basal insulin by 40% to 50% for approximately two hours for every drink consumed. Those who take NPH at night can lower their dose by a similar percentage after drinking. If you choose to eat to offset alcohol’s blood-glucose-lowering effects, choose a food that will take time to affect blood glucose levels such as ice cream, peanut butter, or yogurt. Fifteen to thirty grams of carbohydrate at bedtime should serve as a good starting point.
9. Check often.
10. If it’s broke, fix it.
As the saying goes, the one constant in life is change. The same goes for your diabetes self-care. What worked yesterday may not work today, so don’t hesitate to make changes if you see a pattern of low readings. A single low could be caused by just about anything, but a pattern of lows indicates a problem with your current program.
Strategize to minimize
It may not be possible or practical to implement all 10 strategies at once, so take them one at a time. Try focusing on one each week, and then add another the next week. If in 10 weeks you’re not completely satisfied, you can give me a call or send an e-mail. Maybe we can figure it out together.
Statements and opinions expressed on this Web site are those of the authors and not necessarily those of the publishers or advertisers. The information provided on this Web site should not be construed as medical instruction. Consult appropriate health-care professionals before taking action based on this information.